R=120;
C=33e-12;
tau=R*C;
fprintf ('     \n');
fprintf ('i love IRE MPEI\n');
fprintf ('tau=%f ns\n',tau*1e9);
T=tau*0.01;
fprintf ('T=%f ps\n', T*1e12);
t=0:T:3*tau;
U(1)=0;
S=10;
for k=2:length(t)
    U(k)=(S+tau*U(k-1)/T)/(1+tau/T);
end
plot (t,U);
